这个问题在这里已经有了答案:
9年前关闭。
Possible Duplicate:
UILongPressGestureRecognizer on UITableViewCell - double call
我是 iPhone 新手，
我在长按按钮时显示警报，但是当我长按按钮时，我的警报 View 被再次调用。
这是我的代码片段，
- (IBAction)longPressDetected:(UIGestureRecognizer *)gestureRecognizer {
//Gets text of Button.
UIButton *btn = (UIButton *)[gestureRecognizer view];
BtnText= [btn titleForState:UIControlStateNormal];
NSLog(@"longPressDetected");
UIAlertView* alert_view = [[UIAlertView alloc]
initWithTitle: @"Are you sure want to Delete ?" message:nil delegate: self
cancelButtonTitle: @"Yes" otherButtonTitles: @"No", nil];
[alert_view show];
[alert_view release];
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (buttonIndex==0) {
[self ReloadView];
[alertView dismissWithClickedButtonIndex:0 animated:TRUE];
}
else{
[alertView dismissWithClickedButtonIndex:1 animated:TRUE];
}
}
任何帮助将不胜感激。
编辑:
-(void)viewWillAppear:(BOOL)animated
{
for(int i=0;i<10i++)
{
if(i!=0)
{
if (i%4==0)
{
ypos+=180;
xpos=30;
}
else
{
xpos+=200;
}
}
button = [UIButton buttonWithType:UIButtonTypeCustom];
button.frame = CGRectMake(xpos, ypos, 120,130);
[button setBackgroundImage:[UIImage imageNamed:@"ibook2.png"] forState:UIControlStateNormal];
[button setTitle:[NSString stringWithFormat:@"%@", [Downloadedepubs objectAtIndex:i]] forState:UIControlStateNormal];
[button addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
LongPress = [[UILongPressGestureRecognizer alloc] init];
[LongPress addTarget:self action:@selector(longPressDetected:)];
LongPress.delegate = (id<UIGestureRecognizerDelegate>)self;
[button addGestureRecognizer:LongPress];
[self.view addSubview:button];
[LongPress release];
}
}
最佳答案
UILongPressGestureRecognizer是一个漫长的事件过程。请检查事件状态是否已开始、已完成等。
- (IBAction)longPressDetected:(UIGestureRecognizer *)gestureRecognizer {
if (gestureRecognizer.state == UIGestureRecognizerStateBegan){
NSLog(@"Long press began");
} else if ( gestureRecognizer.state == UIGestureRecognizerStateRecognized ) {
NSLog(@"Long press UIGestureRecognizerStateRecognized");
}
else if (gestureRecognizer.state == UIGestureRecognizerStateEnded) {
NSLog(@"Long press Ended");
}
else {
NSLog(@"Long press detected.");
}
}
我认为，最好使用 UIGestureRecognizerStateBegan 说明你的情况。
请修改您的
longPressDetected()作为 -(IBAction)longPressDetected:(UIGestureRecognizer *)gestureRecognizer {
if (gestureRecognizer.state == UIGestureRecognizerStateBegan){
UIButton *btn = (UIButton *)[gestureRecognizer view];
BtnText= [btn titleForState:UIControlStateNormal];
NSLog(@"longPressDetected");
UIAlertView* alert_view = [[UIAlertView alloc] initWithTitle: @"Are you sure want to Delete ?" message:nil delegate: self cancelButtonTitle: @"Yes" otherButtonTitles: @"No", nil];
[alert_view show];
[alert_view release];
alert_view = nil;
}
}
请检查以下所有 UIGestureRecognizerStates
UIGestureRecognizerStatePossible, // the recognizer has not yet recognized its gesture, but may be evaluating touch events. this is the default state
UIGestureRecognizerStateBegan, // the recognizer has received touches recognized as the gesture. the action method will be called at the next turn of the run loop
UIGestureRecognizerStateChanged, // the recognizer has received touches recognized as a change to the gesture. the action method will be called at the next turn of the run loop
UIGestureRecognizerStateEnded, // the recognizer has received touches recognized as the end of the gesture. the action method will be called at the next turn of the run loop and the recognizer will be reset to UIGestureRecognizerStatePossible
UIGestureRecognizerStateCancelled, // the recognizer has received touches resulting in the cancellation of the gesture. the action method will be called at the next turn of the run loop. the recognizer will be reset to UIGestureRecognizerStatePossible
UIGestureRecognizerStateFailed, // the recognizer has received a touch sequence that can not be recognized as the gesture. the action method will not be called and the recognizer will be reset to UIGestureRecognizerStatePossible
// Discrete Gestures – gesture recognizers that recognize a discrete event but do not report changes (for example, a tap) do not transition through the Began and Changed states and can not fail or be cancelled
UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded // the recognizer has received touches recognized as the gesture. the action method will be called at the next turn of the run loop and the recognizer will be reset to UIGestureRecognizerStatePossible
关于iphone - UIAlertView 在 iPhone 中被调用两次，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11627747/